A web guiding apparatus including a rocking frame provided with a pair of rollers having a web wound around with which web meandering is prevented by causing the rocking frame to rock has been developed (Patent Literature 1).
Patent Literature 1 discloses a web guiding apparatus 100 including a movable table 104 (corresponding to the rocking frame) having a pair of rollers 105,105, as illustrated in FIG. 6(A). The web guiding apparatus 100 includes the movable table 104 rockably provided on both sides thereof (a vertical direction in FIG. 6) by a rocking shaft 103. Guide balls 112 supported by holders 111 are provided at a tip of the movable table 104 (a position away from the rocking shaft 103).
Such a configuration allows the guide balls 112 to support the tip of the movable table 104 when the movable table 104 rocks. This therefore allows the movable table 104 to smoothly rock, thereby being able to prevent web meandering.
Patent Literature 1 also discloses a web guiding apparatus 200 in which movement of a movable table 204 including a pair of rollers 205,205 is supported by link mechanisms 210, as illustrated in FIG. 6(B). The link mechanism 210 includes a pair of shafts 211,212 provided on the movable table 204 and a base 202, and a link member 213 rotatably coupled to the pair of shafts 211,212 and bendably provided between the pair of shafts 211,212.
The web guiding apparatus 200 also allows the link mechanism 210 to support the tip of the movable table 204 when the movable table 204 rocks. This therefore allows the movable table 204 to smoothly rock.
In the case of using the web guiding apparatus 100 in a place such as a paper mill where paper powder, dust, and the like fly in all directions, the paper power and the like may get stuck between the holder 111 and the guide ball 112, causing space therebetween to be blocked with the paper powder. This may prevent the guide ball 112 from smoothly moving or, in the worst case, the guide ball 112 may not move at all. The movable table 104 cannot therefore rock, leading to failure in preventing meandering of a web W.
On the other hand, the web guiding apparatus 200 has higher durability against the paper power and the like compared with the web guiding apparatus 100 having the guide ball 112 held by the holder 111. This is because the pair of shafts 211,212 is coupled to the link member 213 by a bearing or the like.
In the web guiding apparatus 200, a force is applied from a web wound around the pair of rollers 205,205 in an axial direction of the pair of shafts 211,212. As for the force, the web guiding apparatus 200 is, however, inferior to the web guiding apparatus 100 in FIG. 6(A) in durability.
As described above, existing web guiding apparatuses realize both durability against paper powder and the like and durability against a force applied from a web in some extent, however, a web guiding apparatus realizing both of the durability at a higher level has been required.